The chemistry of romantic love
Saturday, 11 October 2008
Syed Fattahul Alim
What is romantic love between sexes? Poets and novelists have been singing love's praises since time out of mind. The infatuation of a boy for a particular girl or of a woman for a man is the subject of most of the dramas and films in the world. The story of Romeo and Juliet by English playwright William Shakespeare or that of Devdas and Parbati by Bengalee writer Sarat Chandra Chattopadhay is some of the most-read and enacted plays on earth. Why are humans so mad about romantic love, which goes against the basic drive of evolution to spread the genes of individuals among as many sex partners as possible? In the animal kingdom, after humans, it is only among the birds that one observes the practice of monogamy and loyal of one individual male to another for a long period. Social scientists have also tried to trace the historical root of the idea of chastity, monogamy, loyalty in married life, etc. It is said that the emergence of these social behaviours has to do with patriarchy, since when the inheritance of property relations started to be determined according to the male person who fathers the children. And loyalty of the mates with one another, in other words, means the female must always prove her loyalty to a particular male to whom she is married. For if the female becomes disloyal, there is the danger that the inheritance may go to wrong heirs. Though a patriarchal society glorifies chastity of women and the loyalty of the wife to her husband, to all intents and purposes, it remains silent about the chastity of the male or his loyalty to a single wife. The males, on the other hand, have the freedom to take as many wives as possible. But the idea of romantic love has nothing to do with property relations. It possibly cuts across social divides. To all probability, it cuts across historical epochs of society. Neuroscientists, on the other hand, have focussed on the chemistry of love and what happens in the brain when a male and a female get attracted towards one another or when they get separated. Jon Pickrell, Lucy Middleton and Alan Anderson of the New Scientist detail below the play of the endocrine glands with rise and fall in the barometer of love between two human beings belonging to opposite sexes.
The word love appears in many contexts: there's maternal love, familial love, romantic love, sexual love, a wider love for fellow humans and religious love for God, to name but a few. Some cultures have ten or more words for different forms of love, and poets and songwriters always find myriad aspects of love to celebrate.
The science of love is still in its infancy. Yet scientists are beginning to get early insights into the nature and origin of love. We can now look inside human brains to view changing patterns of activity and biochemical changes that take place during love, explore diverse human experiences of love, study how we select mates and woo lovers, and look for the evolutionary roots of love.
Addicted to love
So what exactly is going on during the rollercoaster of euphoria and despair that is falling in love?
In the brain, romantic love shows similarities to going mildly insane or suffering from obsessive compulsive disorder. Studies show that when you first fall in love, serotonin levels plummet and the brain's reward centres are flooded with dopamine. This gives a high similar to an addictive drug, creating powerful links in our minds between pleasure and the object of our affection, and meaning we crave the hit of our beloved again and again.
Lust is driven by sex hormones such as testosterone, which can go off-kilter too. As can levels of the stress hormone cortisol, and the amphetamine-like chemical phenylethlyamine, increasing excitement.
Other hormones, oxytocin and vasopressin, kick in later and appear to be crucial for forming long-term partnerships. Couples who have been together for several years show increased brain activity associated with these chemicals, when they look at pictures of their partner. Oxytocin is produced when couples have sex and touch, kiss and massage each other - the hormone makes us more trusting, helps overcome "social fear" and is important for bonding.
Brain scans of people in love show that the old adage "love is blind" really is true. While the dopamine reward areas are excited in love, regions linked with negative emotions and critical social judgement switch off.
Sexual chemistry
Making the right choice when finding true love is an important business, so how do we go about selecting a mate?
Many factors add up to make us desirable to potential partners. There's the obvious stuff like symmetrical features and good skin - which showcase a healthy development, immune system and good genes. Women look for tall men with masculine faces, kindness, wealth and status. Men prefer young, fertile women with a low waist-to-hip ratio and who are not too tall. Neither sex is very keen on people who wear glasses.
Beauty can come at a price however.
Other factors are less obvious. Research suggests that humans are attracted to partners who resemble themselves and - slightly disconcertingly - their parents too. Smell appears to be important as well; people are often more attracted to the smell of those who have different combinations of some immune system (MHC) genes to themselves. Mates with dissimilar MHC genes produce healthier offspring that are better able to thwart disease. People with similar MHC genes even prefer the same perfumes.
Suitors of some species such as birds, and even mice, attract their mates with complex songs or showy displays. Intelligence and talent are prized by people too. As are expensive gifts and even cheap love tokens. Even being in a relationship can make you more attractive to potential mates.
Other factors are more random - a woman's attractiveness and pheromones can fluctuate with her hormone levels and menstrual cycle. As a consequence, taking the pill can inhibit a woman's ability to select an appropriate mate.
In concert, these many factors mean the path to true love can be somewhat unpredictable.
Many people with hectic lifestyles today are turning to the internet, online lonely hearts, dating websites and speed dating to help them track down a partner. Love by wire may have started much longer ago however.
Love evolution
The various forms of love probably have a common evolutionary beginning, so where are scientists looking? Maternal love seems a good place to start. Biologically it makes perfect sense. In animals which help their offspring to survive, the bond is essential to passing the mother's genes on to the next generation.
Again oxytocin may have an important role in the development of a bond between a mother and child. Another hormone, prolactin, may prime both mothers and fathers for parenthood.
Unlike maternal love, monogamous bonds between males and females are pretty rare in mammals. Less than 5 per cent are monogamous, and there is no clear pattern to help explain why it occasionally appears. Monogamy, it appears, is mostly for the birds.
It seems that in those rare mammals that do practise it, evolution stole the biochemistry and neural tricks that bond mother to infant and reinstalled them, so as to bind male and female together. One study of prairie voles shows that a species could be turned from promiscuous to devoted with a change in a single gene related to vasopressin.
Whatever romantic love's origins and purpose, long-term relationships are certainly important in keeping us content and happy.
And love is not only restricted to partnerships between men and women. Though gay relationships are different in some ways, they could be the glue that holds societies together.
Heart-breaking
Unfortunately, it's not all wine and roses when it comes to love. Ecstasy, euphoria, elation and contentment may be accompanied by jealousy, rage, rejection, and hatred.
Falling in love may have evolved because people who focus their attention on a single ideal partner save time and energy, therefore improve their chances of survival and reproduction. Unfortunately, this also means people are pre-disposed to terrible suffering when jilted by their beloved.
Painful emotions develop when the reward centres of the brain, associated with the dopamine high of falling in love, fail to get their hit. Paradoxically when we get dumped we tend to love back even harder, as the brain networks and chemicals associated with love increase. First we protest and attempt to win the beloved back. Panic also kicks in as we feel something akin to the separation anxiety experiences by young mammals abandoned by their mothers.
Then love can turn to anger and hate, as the regions associated with reward are closely linked to rage in the brain. Finally when jilted lovers are resigned to their fate, they will often enter into prolonged periods of depression and despair.
These negative emotions can spawn anything from obsession and domestic violence to stalking and even murder of supposed loved ones.
While such behaviours may be classed as pathological, and perhaps rare, the truth is that they are closer to home than we dare contemplate. Passion's thrills resemble obsessive-compulsive disorder, but in some people, love can conjure up something much more sinister.
The chances of a relationship succeeding would seem to be difficult to predict, but one study suggests that divorce may be partially genetically predetermined. There are even mathematical formulas for predicting the chances of divorce - and for equitably dividing up possessions.
Nevertheless, psychologists have some simple tips for making our relationships last.
What is romantic love between sexes? Poets and novelists have been singing love's praises since time out of mind. The infatuation of a boy for a particular girl or of a woman for a man is the subject of most of the dramas and films in the world. The story of Romeo and Juliet by English playwright William Shakespeare or that of Devdas and Parbati by Bengalee writer Sarat Chandra Chattopadhay is some of the most-read and enacted plays on earth. Why are humans so mad about romantic love, which goes against the basic drive of evolution to spread the genes of individuals among as many sex partners as possible? In the animal kingdom, after humans, it is only among the birds that one observes the practice of monogamy and loyal of one individual male to another for a long period. Social scientists have also tried to trace the historical root of the idea of chastity, monogamy, loyalty in married life, etc. It is said that the emergence of these social behaviours has to do with patriarchy, since when the inheritance of property relations started to be determined according to the male person who fathers the children. And loyalty of the mates with one another, in other words, means the female must always prove her loyalty to a particular male to whom she is married. For if the female becomes disloyal, there is the danger that the inheritance may go to wrong heirs. Though a patriarchal society glorifies chastity of women and the loyalty of the wife to her husband, to all intents and purposes, it remains silent about the chastity of the male or his loyalty to a single wife. The males, on the other hand, have the freedom to take as many wives as possible. But the idea of romantic love has nothing to do with property relations. It possibly cuts across social divides. To all probability, it cuts across historical epochs of society. Neuroscientists, on the other hand, have focussed on the chemistry of love and what happens in the brain when a male and a female get attracted towards one another or when they get separated. Jon Pickrell, Lucy Middleton and Alan Anderson of the New Scientist detail below the play of the endocrine glands with rise and fall in the barometer of love between two human beings belonging to opposite sexes.
The word love appears in many contexts: there's maternal love, familial love, romantic love, sexual love, a wider love for fellow humans and religious love for God, to name but a few. Some cultures have ten or more words for different forms of love, and poets and songwriters always find myriad aspects of love to celebrate.
The science of love is still in its infancy. Yet scientists are beginning to get early insights into the nature and origin of love. We can now look inside human brains to view changing patterns of activity and biochemical changes that take place during love, explore diverse human experiences of love, study how we select mates and woo lovers, and look for the evolutionary roots of love.
Addicted to love
So what exactly is going on during the rollercoaster of euphoria and despair that is falling in love?
In the brain, romantic love shows similarities to going mildly insane or suffering from obsessive compulsive disorder. Studies show that when you first fall in love, serotonin levels plummet and the brain's reward centres are flooded with dopamine. This gives a high similar to an addictive drug, creating powerful links in our minds between pleasure and the object of our affection, and meaning we crave the hit of our beloved again and again.
Lust is driven by sex hormones such as testosterone, which can go off-kilter too. As can levels of the stress hormone cortisol, and the amphetamine-like chemical phenylethlyamine, increasing excitement.
Other hormones, oxytocin and vasopressin, kick in later and appear to be crucial for forming long-term partnerships. Couples who have been together for several years show increased brain activity associated with these chemicals, when they look at pictures of their partner. Oxytocin is produced when couples have sex and touch, kiss and massage each other - the hormone makes us more trusting, helps overcome "social fear" and is important for bonding.
Brain scans of people in love show that the old adage "love is blind" really is true. While the dopamine reward areas are excited in love, regions linked with negative emotions and critical social judgement switch off.
Sexual chemistry
Making the right choice when finding true love is an important business, so how do we go about selecting a mate?
Many factors add up to make us desirable to potential partners. There's the obvious stuff like symmetrical features and good skin - which showcase a healthy development, immune system and good genes. Women look for tall men with masculine faces, kindness, wealth and status. Men prefer young, fertile women with a low waist-to-hip ratio and who are not too tall. Neither sex is very keen on people who wear glasses.
Beauty can come at a price however.
Other factors are less obvious. Research suggests that humans are attracted to partners who resemble themselves and - slightly disconcertingly - their parents too. Smell appears to be important as well; people are often more attracted to the smell of those who have different combinations of some immune system (MHC) genes to themselves. Mates with dissimilar MHC genes produce healthier offspring that are better able to thwart disease. People with similar MHC genes even prefer the same perfumes.
Suitors of some species such as birds, and even mice, attract their mates with complex songs or showy displays. Intelligence and talent are prized by people too. As are expensive gifts and even cheap love tokens. Even being in a relationship can make you more attractive to potential mates.
Other factors are more random - a woman's attractiveness and pheromones can fluctuate with her hormone levels and menstrual cycle. As a consequence, taking the pill can inhibit a woman's ability to select an appropriate mate.
In concert, these many factors mean the path to true love can be somewhat unpredictable.
Many people with hectic lifestyles today are turning to the internet, online lonely hearts, dating websites and speed dating to help them track down a partner. Love by wire may have started much longer ago however.
Love evolution
The various forms of love probably have a common evolutionary beginning, so where are scientists looking? Maternal love seems a good place to start. Biologically it makes perfect sense. In animals which help their offspring to survive, the bond is essential to passing the mother's genes on to the next generation.
Again oxytocin may have an important role in the development of a bond between a mother and child. Another hormone, prolactin, may prime both mothers and fathers for parenthood.
Unlike maternal love, monogamous bonds between males and females are pretty rare in mammals. Less than 5 per cent are monogamous, and there is no clear pattern to help explain why it occasionally appears. Monogamy, it appears, is mostly for the birds.
It seems that in those rare mammals that do practise it, evolution stole the biochemistry and neural tricks that bond mother to infant and reinstalled them, so as to bind male and female together. One study of prairie voles shows that a species could be turned from promiscuous to devoted with a change in a single gene related to vasopressin.
Whatever romantic love's origins and purpose, long-term relationships are certainly important in keeping us content and happy.
And love is not only restricted to partnerships between men and women. Though gay relationships are different in some ways, they could be the glue that holds societies together.
Heart-breaking
Unfortunately, it's not all wine and roses when it comes to love. Ecstasy, euphoria, elation and contentment may be accompanied by jealousy, rage, rejection, and hatred.
Falling in love may have evolved because people who focus their attention on a single ideal partner save time and energy, therefore improve their chances of survival and reproduction. Unfortunately, this also means people are pre-disposed to terrible suffering when jilted by their beloved.
Painful emotions develop when the reward centres of the brain, associated with the dopamine high of falling in love, fail to get their hit. Paradoxically when we get dumped we tend to love back even harder, as the brain networks and chemicals associated with love increase. First we protest and attempt to win the beloved back. Panic also kicks in as we feel something akin to the separation anxiety experiences by young mammals abandoned by their mothers.
Then love can turn to anger and hate, as the regions associated with reward are closely linked to rage in the brain. Finally when jilted lovers are resigned to their fate, they will often enter into prolonged periods of depression and despair.
These negative emotions can spawn anything from obsession and domestic violence to stalking and even murder of supposed loved ones.
While such behaviours may be classed as pathological, and perhaps rare, the truth is that they are closer to home than we dare contemplate. Passion's thrills resemble obsessive-compulsive disorder, but in some people, love can conjure up something much more sinister.
The chances of a relationship succeeding would seem to be difficult to predict, but one study suggests that divorce may be partially genetically predetermined. There are even mathematical formulas for predicting the chances of divorce - and for equitably dividing up possessions.
Nevertheless, psychologists have some simple tips for making our relationships last.